Or the part about how Ridley built Mecha Ridley himself, since that info only comes from an obscure interview with Yoshio Sakamoto on the Japanese website, meaning it's something a casual Metroid fan probably wouldn't know. But I think you're probably right: it's most likely just Pit jokingly questioning Viridi's (somewhat hypocritical) claim that Ridley is "officially […] a narcissist."

Really, there are so many parts of Viridi's statement that Pit could be doubting. I don't know why so many people jump to the conclusion that it's questioning whether or not Zero Mission itself is canon just because it's a remake.